1. Field of the Invention
The present invention relates to methods for sensing the quality of a weld joint.
2. Description of the Prior Art
Traditionally, critical inertia-friction welded joints tend to be difficult to inspect for two reasons: (1) non-destructive evaluation techniques only detect gross disbonds leaving more subtle discontinuities which could have a significant effect on fatigue life or joint fracture toughness; and (2) destructive post-process inspection is time-consuming and costly for highly man-rated or labor intensive applications.
Although improvements in post-process, nondestructive tests have been realized in research and development laboratory environments, such as described in Armstrong, B., Ultrasonic Analysis of Inertia Friction Welds Between Similar and Dissimilar Alloys, M.S. thesis, The Ohio State University, Department of Welding Engineering (1986), the entire contents of which are hereby incorporated by reference, no reliable method is available for detecting in-situ weld quality in a production environment. For commercial applications, weld parameter development and post-process inspection efforts can result in up to a 200%-time (and cost) overhead in the overall manufacturing process with little value added. Therefore, there exists a need for a commercially feasible apparatus and method using an in-process means of determining part quality of a weld joint to reduce costs and increase quality.